Bootstrap下拉子菜单丢失 [英] Bootstrap dropdown sub menu missing

问题描述

Bootstrap 3仍在RC中，但是我只是在尝试实现它.我不知道如何放置一个子菜单类.甚至CSS中都没有类，甚至新文档也没有说什么

Bootstrap 3 is still at RC, but I was just trying to implement it. I couldn't figure out how to put a sub menu class. Even there is no class in css and even the new docs don't say anything about it

在2.x中存在，类名称为dropdown-submenu

It was there in 2.x with class name as dropdown-submenu

推荐答案

已更新2018年

Updated 2018

dropdown-submenu已在Bootstrap 3 RC中删除.用Bootstrap作者Mark Otto的话来说.

The dropdown-submenu has been removed in Bootstrap 3 RC. In the words of Bootstrap author Mark Otto..

子菜单现在在网络上没有什么位置，特别是在移动网络上.它们将在3.0中被删除."-但是，仅需一些额外的CSS，您就能获得相同的功能.

But, with a little extra CSS you can get the same functionality.

Bootstrap 4 (鼠标悬停时导航栏子菜单)

Bootstrap 4 (navbar submenu on hover)

.navbar-nav li:hover > ul.dropdown-menu {
    display: block;
}
.dropdown-submenu {
    position:relative;
}
.dropdown-submenu>.dropdown-menu {
    top:0;
    left:100%;
    margin-top:-6px;
}

导航栏子菜单下拉悬停
导航栏子菜单下拉悬停(右对齐)
导航栏子菜单下拉单击(右对齐)
导航栏下拉悬停(无子菜单)

Navbar submenu dropdown hover
Navbar submenu dropdown hover (right aligned)
Navbar submenu dropdown click (right aligned)
Navbar dropdown hover (no submenu)

引导程序3

以下是使用3.0 RC 1的示例: http://bootply.com/71520

Here is an example that uses 3.0 RC 1: http://bootply.com/71520

以下是使用Bootstrap 3.0.0(最终版)的示例: http://bootply.com/86684

Here is an example that uses Bootstrap 3.0.0 (final): http://bootply.com/86684

CSS

.dropdown-submenu {
    position:relative;
}
.dropdown-submenu>.dropdown-menu {
    top:0;
    left:100%;
    margin-top:-6px;
    margin-left:-1px;
    -webkit-border-radius:0 6px 6px 6px;
    -moz-border-radius:0 6px 6px 6px;
    border-radius:0 6px 6px 6px;
}
.dropdown-submenu:hover>.dropdown-menu {
    display:block;
}
.dropdown-submenu>a:after {
    display:block;
    content:" ";
    float:right;
    width:0;
    height:0;
    border-color:transparent;
    border-style:solid;
    border-width:5px 0 5px 5px;
    border-left-color:#cccccc;
    margin-top:5px;
    margin-right:-10px;
}
.dropdown-submenu:hover>a:after {
    border-left-color:#ffffff;
}
.dropdown-submenu.pull-left {
    float:none;
}
.dropdown-submenu.pull-left>.dropdown-menu {
    left:-100%;
    margin-left:10px;
    -webkit-border-radius:6px 0 6px 6px;
    -moz-border-radius:6px 0 6px 6px;
    border-radius:6px 0 6px 6px;
}

示例标记

<div class="navbar navbar-default navbar-fixed-top" role="navigation">
    <div class="container">
        <div class="navbar-header">
            <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-ex1-collapse">  
                <span class="sr-only">Toggle navigation</span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
            </button>
        </div>
        <div class="collapse navbar-collapse navbar-ex1-collapse">
            <ul class="nav navbar-nav">
                <li class="menu-item dropdown">
                    <a href="#" class="dropdown-toggle" data-toggle="dropdown">Drop Down<b class="caret"></b></a>
                    <ul class="dropdown-menu">
                        <li class="menu-item dropdown dropdown-submenu">
                            <a href="#" class="dropdown-toggle" data-toggle="dropdown">Level 1</a>
                            <ul class="dropdown-menu">
                                <li class="menu-item ">
                                    <a href="#">Link 1</a>
                                </li>
                                <li class="menu-item dropdown dropdown-submenu">
                                    <a href="#" class="dropdown-toggle" data-toggle="dropdown">Level 2</a>
                                    <ul class="dropdown-menu">
                                        <li>
                                            <a href="#">Link 3</a>
                                        </li>
                                    </ul>
                                </li>
                            </ul>
                        </li>
                    </ul>
                </li>
            </ul>
        </div>
    </div>
</div>

P.S. -导航栏中的示例可调整左侧位置: http://bootply.com/92442

P.S. - Example in navbar that adjusts left position: http://bootply.com/92442

这篇关于Bootstrap下拉子菜单丢失的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！